Name ________________________________________ Period ___________ Date ________________
Chapter 12 -- DNA
DNA
 Holds our ____________________ _________________________
 Like a ____________________
 Important for ____________________ to occur
 Biologists had to discover the chemical nature of ____________ to
determine that it is responsible for our genetic information
Griffith and Transformation
 Transformation: when a strain of bacteria is ____________________ by a gene
or genes from ____________________ bacteria
 Experiment
 Inject mice with bacteria containing virus for ________________________
 Smooth colonies = have _____________________ ____________________
 Rough colonies = ____________________ bacteria
 If the virulent colonies were killed with __________________ and mixed with
____________________ bacteria, then the harmless bacteria get
____________________________ into virulent bacteria
 Some factor of the bacteria was ______________________________ to harmless
bacteria
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Avery and DNA
 Wanted to repeat Griffith’s experiment
 Treated heat-killed virulent bacteria with ____________________
 One enzyme destroyed ______________ and ____________________
 Another enzyme destroyed ONLY ________________
 Results showed that bacteria treated with DNA destroying enzyme did
________________ _______________________ harmless bacteria into virulent
bacteria
 It is the ______________ that stores the genetic information from one
generation to the next
Hershey-Chase
 Bacteriophage: a ____________________ that infects ______________________ ONLY
 Scientists wanted to see what gets injected into a bacteria to
____________________ ____________________ infection
 Used a _______________________________ marker for DNA and protein
 After infection, the bacteria that had radioactive marker on DNA
showed that it is the _________________ that is ______________________ into the
bacteria
 Results: _________________ from the ____________________ is what causes
infection
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DNA Structure
 Monomer of DNA is a ___________________________
 ____________________ ____________________
 ____________________________ group
 ____________________________ base
 4 Nitrogenous bases in DNA
 ____________________
 ____________________
 ____________________
 ____________________
 Backbone of DNA is the ____________________ and __________________________
 Nitrogenous bases stick out of side to form ____________________ rungs
 These bases are repeated in a ____________________ that form our
genetic code
 Chargaff’s Rule
 Scientist that discovered a ____________________ between the 4 bases
 Same percentage of _________________________ as ________________________
 Same percentage of _________________________ as ________________________
 Scientists still not sure how they match up though
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 Rosalind Franklin
 Scientist that worked with ________________ ____________________________
 Used X-rays on a portion of DNA and the results showed an _______
pattern
 Watson & Crick
 Scientists that were able to _______________________________ Rosalind’s
X-ray picture
 Result: DNA has a ____________________ ____________________ pattern
where the nitrogenous bases face each other
 DNA has a double helix pattern
 Looks like a ____________________ twisted up
 The sides of the ladder are the ____________________ and
______________________, and the rungs of the ladder are the
________________________________ ____________________ paired up
 The ________________________ binds to thymine
 The guanine binds to _________________________
 This concluded Chargaffs’s rule  __________________ ________________________
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DNA and Chromosomes
 Prokaryotes
 Lack ____________________ and ____________________
 DNA floats as a ____________________ in the cytoplasm
 Eukaryotes
 ____________________ times more DNA than prokaryotes
 DNA is located in ___________________________
 Specific number of chromosomes
 Ex: Humans have _________ chromosomes
 DNA Length
 DNA is very ____________________
 DNA is coiled up into a very small space because it is in
___________________________ form
 Chromosome Structure
 Tightly packed chromatin is wrapped around small proteins
called __________________________
 When chromatin gets super coiled you create a
____________________________
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DNA Replication
 Each strand of DNA is needed to be a ___________________________ for a new
strand of DNA to be produced
 Since you can use one strand to make the other side, they are said to be
______________________________
Duplicating DNA
 Before mitosis occurs, DNA needs to be duplicated first during
__________________________
 When DNA duplicates, it’s called ________________________
 DNA molecules separates into two strands, then produces two new
______________________________strands following the rules of __________________
__________________________
 Each strand serves as a __________________________for the new strand
How Replication Occurs
 Enzymes help make new strands of DNA
 One enzyme called __________________________ “unzips” the DNA,
__________________________the base pairs
 ______________ __________________________adds new bases to pair up with
the template
 This enzyme also __________________________to make sure everything
matches
 What would be the matching bases to the part of DNA shown below?
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Structure of RNA
 Made of __________________________
 ____________________ differences between DNA & RNA
 ______________________
 DNA = _____________________________________ sugar
 RNA = __________________________ sugar
 RNA is __________________________ stranded
 RNA uses __________________________instead of __________________________
to bond with Adenine
Types of RNA
 Three types of RNA
 mRNA
 __________________________ RNA
 rRNA
 __________________________ RNA
 tRNA
 __________________________ RNA
 Messenger RNA
 This is a copy of ________________________________ strand of DNA
 Eventually will ________________ for a __________________________ to be
made
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 Ribosomal RNA
 RNA found in __________________________ (organelles in the cell)
 Ribosomes are the __________________________ for protein synthesis
 Transfer RNA
 Help produce a __________________________ from mRNA
 Brings __________________________ ____________________ (monomer of
protein) to ribosome to bond them together and make a whole
protein
Transcription
 Taking DNA and making an RNA copy
 Occurs in the cell’s __________________________
 ____________ __________________________ opens the DNA and adds RNA copy to
the template
 Once this is made it is called __________________________
RNA Editing
 Pre-mRNA is a ___________________ ___________________ to the final copy of
mRNA
 Some parts of pre-mRNA are not needed to make a protein
 These unnecessary parts are called __________________________
 Introns get _______________ _______________ of pre-mRNA
 Before leaving the nucleus, mRNA needs to get a _____________ and
______________ to finalize the RNA strand
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The Genetic Code
 Proteins are made of 20 possible _____________________ ______________________
 In order to make a protein from a strand of mRNA, the mRNA is read in
a 3 letter sequence called __________________________
 Each three letter codon __________________________ an amino acid
 DNA = AGCGTGCCA
 RNA =
 Codons =
 Amino acids =
 RNA knows when to ______________________ and ______________________ based
on the codons read
 There is _____________________ start codon: _____________
 There are _____________________ stop codons: _____________, _____________,
_____________
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Translation
 Taking mRNA and making a ______________________
 Occurs in the cytoplasm on a ______________________
 ______________ brings specific ______________________ ______________________ to
ribosome
 If mRNA = AUG, then tRNA = UAC
 The tRNA has the _______________________________
 As new tRNA brings amino acids to the ribosome, past ones break off
leaving just amino acids ______________________ to each other
 This continues until one of the three ______________________ codons is met
 Finished amino acid strand goes through __________________ ________________
Mutations
 ______________________ in the DNA sequence that affect the cell
 Two types of mutations
 _________________ ___________________________
 ____________________________ ______________________
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Gene Mutation
 Point mutation
 A change in ________________ nucleotide in a DNA sequence
 Occur only in a ______________________ point of the DNA
 Can ______________________ be a problem
 Frame shift mutation
 A change in the ______________________ ______________________ of DNA
 Since DNA is read in 3 letter codons, if there is an
______________________, ______________________, or large
______________________ in these codons the ______________________ is
changed
Chromosomal Mutation
 A change in the number of ______________________________ in the cell
 Four types
 ______________________
 ______________________
 ______________________
 ___________________________
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